1. Technological Field
The present disclosure relates generally to an antenna apparatus for use in electronic devices such as wireless or portable radio devices, and more particularly in one exemplary aspect to an antenna apparatus for use within a metal device or a device with a metallic surface, and methods of utilizing the same.
2. Description of Related Technology
Antennas are commonly found in most modern radio devices, such as mobile computers, portable navigation devices, mobile phones, smartphones, personal digital assistants (PDAs), or other personal communication devices (PCD). Typically, these antennas comprise a planar radiating element with a ground plane that is generally parallel to the planar radiating element. The planar radiating element and the ground plane are typically connected to one another via a short-circuit conductor in order to achieve the desired impedance matching for the antenna. The structure is configured so that it functions as a resonator at the desired operating frequency. Typically, these internal antennas are located on a printed circuit board (PCB) of the radio device inside a plastic enclosure that permits propagation of radio frequency waves to and from the antenna(s).
More recently, it has been desirable for these radio devices to include a metal body or an external metallic surface. A metal body or an external metallic surface may be used for any number of reasons including, for example, providing aesthetic benefits such as producing a pleasing look and feel for the underlying radio device. However, the use of a metallic enclosure creates new challenges for radio frequency (RF) antenna implementations. Typical prior art antenna solutions are often inadequate for use with metallic housings and/or external metallic surfaces. This is due to the fact that the metal housing and/or external metallic surface of the radio device acts as an RF shield which degrades antenna performance, particularly when the antenna is required to operate in several frequency bands.
Accordingly, there is a salient need for an antenna solution for use with, for example, a portable radio device having a small form factor metal body and/or external metallic surface that provides for improved antenna performance.